Climate Change and Biodiversity in King County

The effects of climate change are only beginning to be understood in King County, though they have already begun. Some of the impacts of climate change on biodiversity we expect include:

Increases in direct mortality as a result of thermal stress. In other words, like heat stress can kill people, higher air and water temperatures will kill some plants and animals. Salmonids and freshwater mollusks will be most vulnerable in our aquatic systems. Many native plants that have adapted under milder conditions may not survive hot summers or freezing winters.

Altered growth rates and timing of life history events. Life cycles of predators may no longer match up with those of prey. So when an entire population of a species needs to eat but doesn't have food, they may die or move elsewhere. The same may be true for migratory animals who arrive to find their food source is not ready to be eaten yet. Or if babies of one species are born at a time when their food is not yet available or already came and went.

Altered local distributions and regional range shifts. Salmon and char, freshwater mollusks, and alpine species of plants and animals may be greatly impacted. Ecological systems at high elevations will show some of the most obvious effects of climate change. As temperatures increase, treeline is expected to move upslope. Therefore, alpine meadows will shrink. Species that rely on high elevations will be forced up slope until there is nowhere else to go.

Biological invasions. Exotic marine fishes, invasive freshwater fishes, aquatic and terrestrial plants, and more are already a problem. With earlier growing seasons and warmer overall temperatures, new opportunities will open up for more invasions.

Food web disruptions. Breakdown of certain parts of the phytoplankton-zooplankton food web may occur. Because these microscopic animals form the base of the food chain in our region, if these systems break down, the effects could be dramatic as the ocean food chain snaps in many places.

Conserving biodiversity in the face of a changing climate

In the face of climate change, biodiversity conservation may be of critical importance for buffering the effects of rising temperatures on regional ecosystems, damping the rates of ecological change, and reducing the potential for sudden, extreme changes in the environment. Given the interlinkages that exist between climate change and biodiversity the Convention on Biological Diversity, on their About Climate Change and Biological Diversity web site, highlights the need to:

identify and conserve biodiversity components that are especially sensitive to climate change,

preserve intact habitats so as to facilitate the long-term adaptation of biodiversity,

improve our understanding of the climate change/biodiversity linkages, and

Impacts on some of our plants and animals

The report, Climate Change and the future of Biodiversity in Washington, prepared for the Washington State Biodiversity Council by Joshua J. Lawler and Molly Mathias provides a review of changes expected throughout Washington State. The report provides the most comprehensive review to date for what changes are likely to be seen in Washington’s ecological systems and species. They point out that "Conservation planning efforts are generally based on the current distribution of biodiversity. However, as climate changes, species will clearly move in response to physiological temperature constraints, changes in habitat, food availability, new predators or competitors, and new diseases and parasites." -Lawler and Mathias 2007.

frogs and salamanders

Amphibians are likely to be some of the most susceptible animals to climate change for several reasons:

They have very specific habitat needs for protective cover, temperatures, and moisture levels, including available open water

They are limited in their abilities to move to different locations

Amphibians are thin-skinned. It is not an insult, it's true. Their thin skin makes frogs acutely sensitive to even minor changes in temperature, humidity, and air or water quality.

Their thin skin also makes frogs more susceptible to chytrid fungus, which is devastating amphibian populations. A new study suggests that temperature extremes may have previously helped keep the deadly disease in check, but new climate cycles are now altering annual temperature changes.

mammals

It is likely that mammals relying on higher-elevation habitats will be most affected by climate change. The pika is one example. Pikas are small mammals in the rabbit family that lives on rocky slopes at high elevations. They have already experienced several population extinctions throughout the west over the last 50 years. Pikas can only leave their burrows to forage when temperatures are cool enough. As the climate warms, they are able to spend less and less of each summer day foraging and consequently are able to store less and less forage for the long winter. And in fact, some wildlife advocates have sued the Federal Government to list the Pika under the Endangered Species Act. See the news article on the side banner for additional information.

birds

White-tailed Ptarmigan. Photo by J. Vanderhoof.

Birds, more than many other animals, will be able to move as changing climate alters their habitats. They will continue to shift their ranges both poleward in latitude and upward in elevation in response to warming trends (they have already started doing so). This means that some birds, like the Western Scrub-jay, whose current range is just south of King County may become more common. It also means that birds like the White-tailed Ptarmigan, whose habitats are currently at 7000 ft and higher, may leave the County's alpine areas altogether, whereas birds like Spruce Grouse may move higher than 4000 ft elevation, which is their current lower limit.

The birds page provides a lot of additional information about birds found in King County.

freshwater fish

As water temperatures increase, warm-water fish species will expand their ranges, cool- and cold-water fish species will have a decrease in available habitat. This may mean an increase in competition between non-native fish such as smallmouth bass and native salmon and trout species as well as an overall reduction in populations of our native cold-water species. So, fewer salmon, more non-native fish. But nothing is ever that simple and straightforward.

In addition to potential dissolved oxygen stress resulting from increased water temperatures, salmon and trout may not have enough food if their prey are not available when the salmon need them. On top of that, stress makes animals more susceptible to disease, predation, competition, and other physiological problems. In addition, depending on what happens to stream waters, some important habitats may disappear altogether at critical times of the year -- some streams may dry up during the end of dry summers.

But it still isn't that simple... The flip side is that some ecosystem shifts could actually benefit salmon. For example, changes could result in more high-energy prey resources that are somehow not available to competitors. Variability and uncertainty make prediction a very tricky business.

insects

Some of the largest climate-driven impacts to ecological as well as agricultural and forestry systems may be mediated by changes in insect populations. For starters, changes in timing, known as phenological changes, that result from climate change could disrupt countless systems. For example, advances in flowering dates have the potential to create mismatches between pollinators and plants, between parasites and hosts, and between herbivores and their food resources. Forest pests and pathogens are already known to be expanding their ranges in response to climate change.

marine forage fish

Forage fish are another poignant example of the complex web of reactions that can ensue with a changing climate. Marine forage fish, including Pacific sandlance, surf smelt, and Pacific herring are the base of the food web for many species, including but not limited to salmon, marine birds, and orca whales. These forage fish have discreet spawning habitat requirements along the shoreline, including eelgrass beds for Pacific Herring and upper intertidal beach areas for Pacific sandlance and surf smelt. This habitat is located along the same shoreline that is impacted by people building bulkheads in an attempt to limit erosion of their property (see the case study below).

Marine Shorelines, a Case Study

Forage fish and their habitat beautifully illustrate (in a storm-is-brewing sort of way) the complex web of reactions that can ensue with a changing climate. As mentioned above, marine forage fish, including Pacific sandlance, surf smelt and Pacific herring, are important prey for many species, and they have discreet spawning habitat requirements along the shoreline. This habitat is located along the same shoreline that is impacted by people building bulkheads in an attempt to limit erosion of their property. Intertidal areas (areas that are under water at high tide and exposed at low tide) are heavily impacted by the bulkheads.

The impacts of these bulkheads (also known as sea walls) are many and varied:

Bulkheads were historically built at or below the elevation the where forage fish spawn, so their spawning habitat was completely and permanently buried.

Bulkheads generally stop natural erosion by restricting sand and gravel from replenishing the beach and spawning habitat. Over time, the beach that remains in front of a bulkhead will disappear and cause the bulkhead to collapse

Bulkheads can increase the wave energy directly in front of the bulkhead. In other words, the water will crash harder into this location and wash away sand and smaller sediment. Not only does this change of substrate mean different animals would live there, but it the larger sediment is too coarse for forage fish to spawn in.

Bulkheads generally do not allow for organic debris (drift logs, algae) to build up on the beach. Organic debris also forms the basis for portions of the food web.

As sea levels rise with climate change, the amount of beach habitat will become squeezed between the higher waters and the bulkheads. This squeezing will further reduce the overall forage fish spawning habitat available.

It is likely that more bulkheads will be built in response to increased erosion caused by the toe of the marine bluffs interacting more frequently with Puget Sound. More bulkheads will further compound the negative impacts.

This feedback cycle will further compound the negative impacts of climate change and development on forage fish.

In King County, the most heavily impacted area in terms of bulkheading are the older developed areas, which includes Seattle and the shoreline north along the railroad corridor, which has been in place for over a hundred years. Federal Way and Vashon are currently the least impacted by bulkheads. But Alki Beach, Lincoln Park, and Golden Gardens still have sand, despite all the development and lack of bluff erosion. How is this possible? You can thank City of Seattle for trucking in sand to keep these recreational areas functioning.

Related Climate Information - King County Climate Planning

Some predicted climate change impacts to the Pacific Northwest and King County include:

Increased average annual temperatures, increased temperatures across all seasons, significantly increased summer temperatures, and increased urban “heat island” effects, in which urban air and surface temperatures are higher than in the Rural Area due to storage of heat in pavement and buildings;